As the world looks to the increasing use of autonomous vehicle there is new evidence that the computers needed to control them will pose a significant greenhouse gas threat.

Scientists at MIT say in the future, the energy needed to run the powerful computers on board a global fleet of autonomous vehicles could generate as many greenhouse gas emissions as all the data centres in the world today.

The researchers explored the potential energy consumption and related carbon emissions if autonomous vehicles are widely adopted, and have concluded that there needs to be a way to make the computers far more efficient if they are to drive towards a net zero future.

Their research found the data centres that house the physical computing infrastructure used for running applications are widely known for their large carbon footprint: They currently account for about 0.3 percent of global greenhouse gas emissions, or about as much carbon as the country of Argentina produces annually, according to the International Energy Agency.

Realising that less attention has been paid to the potential footprint of autonomous vehicles, the MIT researchers built a statistical model to study the problem. They determined that 1 billion autonomous vehicles, each driving for one hour per day with a computer consuming 840 watts, would consume enough energy to generate about the same amount of emissions as data centres currently do.

The researchers also found that in over 90 percent of modelled scenarios, to keep autonomous vehicle emissions from accelerating past current data centre emissions, each vehicle must use less than 1.2 kilowatts of power for computing, which would require more efficient hardware. In one scenario — where 95 percent of the global fleet of vehicles is autonomous in 2050, computational workloads double every three years, and the world continues to decarbonize at the current rate — they found that hardware efficiency would need to double faster than every 1.1 years to keep emissions under those levels.

“If we just keep the business-as-usual trends in decarbonisation and the current rate of hardware efficiency improvements, it doesn’t seem like it is going to be enough to constrain the emissions from computing onboard autonomous vehicles. This has the potential to become an enormous problem. But if we get ahead of it, we could design more efficient autonomous vehicles that have a smaller carbon footprint from the start,” explained first author Soumya Sudhakar, a graduate student in aeronautics and astronautics.

The researchers said they want to continue exploring hardware efficiency and algorithm improvements. In addition, they say their model can be enhanced by characterising embodied carbon from autonomous vehicles — the carbon emissions generated when a car is manufactured — and emissions from a vehicle’s sensors.

While there are still many scenarios to explore, the researchers hope that this work sheds light on a potential problem people may not have considered.

“We are hoping that people will think of emissions and carbon efficiency as important metrics to consider in their designs. The energy consumption of an autonomous vehicle